View Single Post
  #109   Report Post  
Jeff Morris
 
Posts: n/a
Default Inherently beautiful.

After starting this little brouhaha I think I might have to modify my claim that my cat
has no prop walk.

Since the props are widely spaced (15 feet with an 18 foot beam) if I ever tried to back
on one engine the boat would "spin out" immediately. Although the boat is functional with
one engine in forward, it is rather crippled for maneuvers in reverse.

Therefore, anytime I would be running one engine in close quarters, I would be also be
running the other, and likely balancing so that it would back true, or adjusting to turn
as desired. The only way I could tell that I had no prop walk would be to carefully
measure the RPMs, and this is beyond my instrumentation.

Thus, the net affect is zero propwalk, but I have no way to determine whether the
individual engines are generating propwalk.

BTW, the builder claimed this was a non-issue, but when they started building larger
sailing cats, and the powercat, they used counter-rotating props, because it was an option
with the larger transmissions.


"Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom wrote in message
...
My props are Left-Hand, two blade folding. There is virtually no propwalk. I'm quite
familiar with the phenomenon because my old Nonsuch would walk hard to port, as would

all
the single screw boats I've driven.

I was under the impression that a major contributor to prop walk was the angle of the
shaft; thus, if its horizontal, the affect is greatly reduced. If this isn't the case,
what does cause it?

-jeff



"Shen44" wrote in message
...
Subject: Inherently beautiful.
From: "Jeff Morris" jeffmo@NoSpam-sv-lokiDOTcom
Date: 10/22/2003 13:00 Pacific Standard Time
Message-id:

Neal really doesn't understand, even though I explained it fully. He'll
figure it out and
come up with a creative way to cover his ignorance!

BTW, I get virtually no prop walk - is that because the shaft is horizontal,
the blades
are flat, the keel is long, or a combination of all three?


None of the three SHOULD eliminate "prop walk", singly or in combination ....
G you don't have Kort nozzles, do you?
To be sure I'm thinking correctly, both your props are right hand, folding? (I
have no experience with folding, so I don't know if this may be a factor).

When backing, your boat, should want to back to port, as Neal said, once you
lose steerageway .... does it? (assuming two right hand props ... I can't
remember if you said right or left).

Shen